What software version are they? What video card do each of the units have? Are you feeding a live input source?
If you do either of the video self-test patterns does the problem go away?
A bit more info as to what exactly you are seeing, and what steps you are using to get to the problem will help.
Based on the very little info you have provided I would check to see that the RGBHV connectors on the back of the projector are hooked up and seated properly.
